Various structures for beverage dispensing heads are well-known for dispensing single-flavor or multiple-flavor drinks in a post-mix operation, that is, where the constituent components of the beverage are combined outside of a bottling plant and dispensed into an individual container, e.g., a cup or glass for the end consumer. The dispense head can either be stationary, that is, mounted to some stand or dispensing machine where the cup is moved into a proper orientation for receiving the beverage; or mobile, where the dispense head is connected to the end of a length of hose and can be manually manipulated into a proper dispensing orientation for the cup. The nozzle of the dispense head generally directs a diluent such as carbonated water or plain water, and one or more concentrated flavors and/or sweeteners, together into a cup. The concentrate is typically mixed in a ratio of about 1:5 with the diluent, although this can vary with the concentrate and diluent.
Patent specification U.S. Pat. No. 4,218,014, for example, shows a dispensing head for multiple flavors where a diluent is directed through an outlet passage in a nozzle to individual outlet runners spaced around a convex conical bottom surface of the nozzle and directed outwardly away from the centerline of the nozzle. A plurality of concentrate outlets are also provided around the convex conical bottom surface of the nozzle in alternating relation with the diluent outlets. A spout with a bottom opening surrounds the nozzle and extends downwardly past the bottom surface of the nozzle and concave inwardly to define a torroidal diluent flooding chamber. The diluent is introduced through the outlet passage and outlet runners to the flooding chamber and against the flooding chamber concave wall surfaces, which shape and direct the flow. The diluent flow then discharges in "an absolutely straight column" from the bottom opening in the spout. The concentrate stream is directed at high velocity through the flowing water and also against the inner concave surface of the spout, which shapes the concentrate into a "disc shape" within the nozzle and directs the concentrate into the water stream, where it is dissolved and discharged with the water through the bottom opening in the spout.
Patent specification GB 2269761 also shows a multi-flavor dispensing nozzle where concentrate is directed through individual centrally-located passages, and diluent is directed through individual peripheral passages, spaced around the central passages. The concentrate and diluent are mixed together in a mixing cavity formed by the housing of the nozzle before being directed downstream out of the nozzle.
A single-flavor mixer nozzle is shown in patent specification GB 2244977, where concentrate is first directed into a syrup accumulator chamber, and then directed past a syrup diverter into a mixing chamber to mix with a first flow of diluent from a accumulator chamber, the first mixture then being directed to an annular discharge orifice creating a "donut-shaped" flow pattern. The first mixture is then mixed with a second flow of diluent passing around a bulb-shaped nozzle cone which causes the second diluent to flow in a cone-shaped column which converges with the donut-shaped flow of the first mixture, and then mixes with the first mixture as the combined mixture falls downwardly into the cup.
Other known single-flavor dispensing valves are shown in patent specification U.S. Pat. No. 4,936,488, where in one embodiment a water port is concentric with and partially surrounds a central concentrate port, with the concentrate port being inwardly set from the water port for at least initially mixing the concentrate and diluent within the nozzle; and in another embodiment a conical nozzle with an inner cylindrical surface directs an outer flow of diluent in surrounding relation to a central elongated syrup diffuser, the diffuser having a syrup distributor at the tip thereof which is inwardly set from the lower opening of the nozzle - again for mixing the concentrate and diluent at least partially within the nozzle before the mixture is directed downstream.
A similar single-flavor dispensing valve is shown in patent specification U.S. Pat. No. 2,674,264, where a series of individual diluent outlet ports are evenly-spaced in a circumferential array around a central concentrate outlet port. The diluent outlet ports direct the diluent radially inward toward the concentrate in a recess of the nozzle, with the mixture then passing downstream through a lower opening in the nozzle. Patent specification GB 2256636 shows a similar structure, however the individual diluent outlet ports direct the diluent radially inward toward the concentrate at a location downstream from the nozzle head.
Some known factors which are important in beverage dispensers include mixing of the diluent and concentrate; foaming; excessive loss of carbonation; and manufacture, clean-up, and service costs. Insufficient mixing of the beverage is a particular concern and includes the problems of residue, carryover and stratification. Residue is where concentrate remains in the head after the dispense of the concentrate is complete. If a small amount of residue is present, the residue can dry within the head between beverage draws and clog the nozzle; while if a greater amount of concentrate is present, the residue can drip down into a collection tray under the dispense head or onto a countertop. These problems can be unsightly and cause unpleasant odors, and generally raise sanitary concerns. Carryover is similar, but relates to the mixing of concentrate left within the dispense head from a previous beverage of one flavor (or color) with a subsequent beverage of a different flavor and/or color. Carryover can be caused by post-dripping or by the suction produced by the beverage nozzle when dispensing one flavor, which can cause concentrate of another flavor to be drawn out of the dispense passage and carried into the beverage stream, or force the concentrate up a dispensing passage of another concentrate by back-pressure or reverse flow. These problems raise beverage quality issues when color and taste are important. Stratification is where the diluent and concentrate are not fully and evenly mixed, and the concentrate, being of a higher density, generally settles toward the bottom of the container, while the diluent is disposed towards the top of the container.
One of the more difficult of the above-mentioned problems to overcome is that of residue, that is, where some concentrate and/or mixed beverage remains on the inside surfaces of the nozzle after the dispensing process is complete, where the concentrate can dry, or coalesce and drip down from the nozzle. It is believed that this occurs because many of the prior nozzles use the inside wall surfaces of the nozzle to shape and direct the fluid flow through the nozzle during the mixing process. However, once the concentrate is mixed with the diluent and exposed to air, bacterial growth can occur. With the nozzles typically having a long, cylindrical shape with a tapered spout area, it can be difficult to adequately clean the inside wall surfaces of the nozzle without disassembling the dispense head and separately washing the nozzle in a disinfectant solution. The collection trays and countertops which collect dripping concentrate also have to be frequently cleaned and drained to prevent bacterial growth. It can therefore be difficult and time-consuming with some prior art nozzles to keep the inside surfaces of the nozzles and related equipment clean during continual usage to maintain necessary sanitary conditions and operation of the dispensing machine.
Some of the known nozzles have apparently been designed in an attempt to overcome some of the above drawbacks. However, it is believed that the known nozzles still have performance limitations in dispensing a beverage, particularly with respect to the thorough mixing of the constituent components of the beverage and the easy clean-up of the dispense head and related equipment.
As such, it is believed that there is a demand in the industry for a dispensing head for beverages which addresses many of the above drawbacks, for example the clean-up requirements and the thorough mixing of the beverage during the dispense process. Of course it is believed that there is a continual demand for new and unique post-mix dispense heads which eliminate or at least significantly reduce residue, carryover and stratification, as well as foaming and loss of carbonation, but which nonetheless provide a design which is economical to manufacture, and simple to clean and service.